Known in the art are apparatus for electrohydroblasting trimming of castings, wherein the castings being trimmed are placed in a bath containing a working fluid. The bottom part of the bath narrows for the collection of slime. The sludge is removed by means of a pump (cf. the USSR inventor's Certificate No. 415091, cl. B22 D, 1980; U.S. Pat. No. 4,198,995, C1.B08B 3/10).
Molding sand is removed during the electrohydroblasting trimming. A part of large-size lumps of the sand is thrown out from the container during the electrohydroblasting trimming, gets to the bottom part of the bath and clogs the pump so as to cause the suspension of operation and cleaning of the pump. Installation of filters at the inlet cannot give useful results as the filter is also rapidly clogged with large-size particles.
In addition, in pumping the working fluid containing a large quantity of core sand rapid wear of pump members occurs owing to the presence of abrasive particles in the core sand so that the pump members removing the sludge must be frequently replaced.